Method of manufacturing a waterproof connector housing

ABSTRACT

A method of manufacturing a waterproof connector housing, that enables the formation of a uniform packing ring which is an integral part of the housing by engaging a hollow body of a housing with a trapezoidal engaging portion provided on a male mold, holding the housing by contacting tightly an inner wall of the hollow body with the trapezoidal engaging portion to align the center of the male mold with that of the housing, and injecting a rubber material into a packing ring forming space uniformly defined by one of both of the male and female mold through a rubber supply paths of the housing. The housing having the hollow body with tapered shoulder, a male mold having the trapezoidal engaging portion and a female mold beveled or thinned at the open edge are employed for implementing the method.

This application is a continuation of application Ser. No. 08/506,337filed Jul. 24, 1995, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of manufacturing a waterproofconnector housing in which formed is a packing ring which constitutes anintegral part of the housing, and to a housing and apparatus to beemployed in such method.

2. Description of the Prior Art

In Japanese Patent Application Laid Open No. Sho 63-221568, there isdisclosed, as shown in FIG. 10, a method of manufacturing a waterproofconnector housing wherein formed is a packing ring which is an integralpart of the housing.

In accordance with the method shown in FIG. 10 herein, a housing (a),which is separately formed, is located between a male metal mold (b) anda female metal mold (c), and a rubber material is introduced through arubber supply path (e) into a space (d) provided at the male metal mold(b) for forming a packing ring. In this manner, a packing ring, which isan integral part of the housing, has been formed.

According to the above described manufacturing method, however, whenthere is a dimensional difference from an intended size of the housing(a) which is held in the molds, a clearance (so-called a play) is formedbetween the male metal mold (b) and the housing (a), as is shown in aspecific diagram of FIG. 11, so that the center of the male metal mold(b) and that of the housing (a) are out of alignment and the housing (a)may be placed at an off-centered position. Since the off-centeredpositioning of the housing (a) results in a variation of a width of thespace (d) depending on the angular location, the thickness of the formedpacking ring may vary at places, such as a thin portion (f) and a thickportion (g), so that the function of waterproofing by thus formedpacking ring is degraded and unusable, and defective units have beenproduced.

To prevent the housing (a) from the off-centered positioning, the centerof the male metal mold (b) and that of the housing (a) should be alignedwith each other. Accordingly, it has been necessary to particularlyprepare respective male metal molds (b) for preformed housings (a).Further, if housings are manufactured in a multiple cavity production,the same number of metal molds have to be prepared, and such metal moldsare also required a high accuracy, this results in an increase ofmanufacturing costs and problems encountered with such complicatedmanufacturing process.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to eliminate theproblems encountered with the prior art methods, to provide a method ofmanufacturing a waterproof connector housing wherein a housing can beeasily placed on a predetermined position of a metal mold prior toforming a packing ring which is an integral part of the housing, toprovide a uniformly formed packing ring, and to provide a housing and anapparatus to be employed for such method of manufacturing.

To achieve the above objective, according to one aspect of the presentinvention, there is provided a method of manufacturing a waterproofconnector housing, wherein a formed housing is placed between male andfemale metal molds and a rubber material is introduced into a packingring forming space which is provided at one or both of the male andfemale metal molds so as to form a packing ring which is an integralpart of the housing, comprising the steps of engaging the housing with atrapezoidal engaging portion provided on the male metal mold, andintroducing the rubber material after contacting an inner wall of thehousing tightly with the engaging portion of the male metal mold.

According to another aspect of the present invention, there is provideda method of manufacturing a waterproof connector housing, wherein aformed housing is placed between male and female metal molds and arubber material is introduced into a packing ring forming space which isprovided at one or both of the male and female metal molds so as to forma packing ring as an integral part of the housing, comprising the stepsof providing tapered protrusions on an outer wall of the housing, whichprotrusions increase their height along a direction toward an open endof the female metal mold, pressing the tapered protrusion with an innerwall of the female metal mold to bring the housing tightly in contactwith the female metal mold when the female metal mold is mounted, andintroducing the rubber material.

According to still another aspect of the present invention, there isprovided a housing, which is for manufacturing a waterproof connectorhousing having a packing ring which is an integral part of the housing,being characterized in that tapered protrusions are provided on an outerperipheral wall of the housing and in the proximity of openings ofrubber supply paths, which tapered protrusions are formed in such amanner as to increase their heights along a direction toward a junctureof the male and female metal molds.

According to yet another aspect of the present invention, there isprovided an apparatus for producing a waterproof connector housinghaving male and female metal molds each of which has an engaging portionfor the housing and rubber supply paths and a packing ring forming spaceat one or both of the male and female metal molds, wherein the housingis placed between the male and female metal molds and a rubber materialis introduced into the packing ring forming space through the rubbersupply paths to form a packing ring which is an integral part of thehousing, being characterized in that a trapezoidal engaging portion isformed on the male metal mold and an inner wall of the housing istightly contacted with the trapezoidal engaging portion.

It is preferable for the female metal mold to provide an inclinedsurface at a portion where contacts with the housing.

According to said one aspect of the present invention, since a hollowbody of a housing engages with the trapezoidal engaging portion formedon the male metal mold and that the engaging portion of the male metalmold is tightly contacted with the inner wall of the hollow body of thehousing, even when there is a small dimensional error at the innerdiameter of the hollow body, the hollow body of the housing can be heldtightly at the position where the outer diameter of the trapezoidengaging portion of the male metal mold matches with the inner diameterof the hollow body, and the center of the engaging portion can bealigned with the center of the housing. Therefore, a packing ring havinga uniform thickness can be formed as an integral part of a housing.

According to said another aspect of the present invention, after ahousing having tapered protrusions, which are used as stocks for forcefitting, on its outer wall being mounted on the male metal mold, sincethe housing and a female metal mold are contacted tightly by pressingthe tapered protrusions with the peripheral wall of the female metalmold when both of them are engaged, it is possible to provide a tightfitting between the tapered protrusion and the peripheral wall of thehousing at all times. Thus, even when there is a small variation in sizeat the inner wall of the housing, the center of the female metal moldand that of the housing can be aligned with each other. This enables themethod to form a packing ring, which has a uniform thickness, as anintegral part of the housing.

According to said still another aspect of the present invention, sincethe tapered protrusions are increase their height along a directiontoward the juncture of the two metal molds in the proximity of openingsof rubber supply paths, the housing is firmly and tightly contacted withthe female metal mold by the act of tapered protrusions even if there isa slight difference in size at the outer wall of the housing, whereassuch difference is compensated by the tapered protrusion. Therefore, thealignment of the center of the housing with that of the metal mold isfacilitated.

According to said yet another aspect of the present invention, since theengaging portion of the male metal mold is formed into a trapezoidalshape, it is possible to hold the hollow body of the housing tightly atthe trapezoidal engaging portion of the male metal mold, at where itsouter diameter coincides with the inner diameter of the hollow body ofthe housing, even if there is a slight difference in size at the hollowbody of the housing, the hollow body can be held tightly by the engagingportion at where an outer diameter of the trapezoidal engaging portioncoincides with an inner diameter of the hollow body, thereby the centerof the housing and that of the metal mold can be easily aligned witheach other.

Further, by providing the female metal mold with an inclined surface tobe contacted with the housing, an up-and-down movement of the housing isprevented from causing and then the housing can be held securely, andthe accuracy is greatly improved in forming of a packing ring.

In addition, according to the present invention, since the center of thehousing and the center of the metal mold can be easily aligned with eachother, the rubber material is prevented from leaking during the processof manufacturing the packing ring and that defective products from beingproduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a male metal mold and a female metalmold according to an embodiment of the present invention;

FIG. 2 is a partial cross-sectional view of a housing held between themale and female metal molds of FIG. 1;

FIG. 3 is a cross sectional view of a housing held between the male andfemale metal molds of FIG. 1;

FIG. 4 is a partial cross-sectional view of a housing according toanother embodiment of the present invention;

FIG. 5 is a plan view of the housing of FIG. 4;

FIG. 6 is an explanatory diagram showing a tapered protrusion on thehousing of FIG. 4;

FIG. 7 is a cross-sectional view of a female metal mold and a male metalmold according to still another embodiment of the present invention;

FIG. 8 is a cross-sectional view in which a housing is held between themale and female molds of FIG. 7;

FIG. 9 is an explanatory diagram showing a state wherein a peripheralwall of the female metal mold of FIG. 7 presses a tapered protrusion onthe housing;

FIG. 10 is an explanatory diagram of a conventional method forintegrally forming a packing ring for a housing; and

FIG. 11 is an explanatory diagram showing a state wherein the housing iseccentrically positioned relative to the male metal mold of FIG. 10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now referring to FIG. 1, there is shown a cross-sectional view of a malemetal mold 1 and a female metal mold 2 according to one preferredembodiment of the present invention.

As is shown in FIG. 2, the male metal mold 1 and the female metal mold 2constitute a set of upper and lower molds to be employed for forming apacking ring which is an integral part of a housing 3.

The male metal mold 1 has a trapezoidal engaging portion 4 at itscentral portion, a housing retaining portion 5 around the engagingportion 4 being defined by a predetermined gap, and a peripheral wall 6communicated with a base 4a of the engaging portion 4 at the bottom ofthe retaining portion 5.

The engaging portion 4 is employed to be engaged with and mounted on ahollow body 7 of the housing 3. A configuration of the engaging portionis so arranged that a diameter of the base 4a is slightly larger thanthat of an inner wall 7a of the hollow body 7, a top end 4b is smallerthan the diameter of the inner wall 7a of the hollow body 7, and adiameter of the engaging portion is gradually reduced from the base 4ato the top end 4b to provide a trapezoidal shape. A space 8 for forminga packing ring is provided at the periphery of the top end 4b.

When the housing 3 is engaged with the engaging portion 4, the housingis contacted tightly with the engaging portion 4 at a portion where thediameter of the trapezoidal engaging portion 4 equals to the diameter ofthe inner wall 7a of the hollow body 7 of the housing 3, as is shown inFIG. 3. Hence, the center of the housing 3 is aligned with the center ofthe engaging portion 4. In other words, automatic positioning orcentering of the housing 3 with the male metal mold 1 is performed.

The female metal mold 2 is a mortar shaped metal mold to be mounted onthe male metal mold 1. A thin, beveled portion 10 tapered towards theopening is formed at the open edge of the peripheral wall 9 of thefemale metal mold, and rubber supply paths 11 and 11' for introducing arubber material to form the packing ring are provided at symmetricalpositions of the beveled portion or tapered surface 10.

When the female metal mold 2 is mounted on the male metal mold 1 whichis engaged with the housing 3, as is shown in FIG. 3, the taperedsurface 10 of the female metal mold 2 is brought into a close contactwith the tapered peripheral wall 7b of the housing 3 and holding thehousing 3 in position.

As is shown in FIG. 2, the housing 3 comprises the hollow body 7 and aterminal retaining portion 12. Rubber supply paths 13 and 13', whichpenetrate through the hollow body 7, are formed at locations where arein close to the juncture of the hollow body 7 and the terminal retainingportion 12 in order to communicate with the rubber supply paths 11 and11' of the female metal mold 2. The rubber supply paths 13 and 13' areprovided to penetrate the tapered peripheral wall 7b of the hollow body7.

After the female metal mold 2 has been mounted on the male metal mold 1,a rubber material is injected into the space 8 through the rubber supplypaths 11 and 11' to form a packing ring of the housing 3. The rubbermaterial is not limited to a specific composition, but preferably, is aliquid silicone rubber of an addition reaction type containing 75ppm/cm³ of siloxane, which has a low boiling point than that of (CH₃)₂SiO!₁₋₁₀. A liquid silicone rubber layer is formed on the housing 3 and,by vulcanizing the thus formed liquid silicone rubber layer, a packingring is formed as an integral part of the housing 3.

FIG. 4 is a side view of a housing 14 according to another preferredembodiment of the present invention, and FIG. 5 is a plan view of thehousing of FIG. 4. The housing 14 comprises a hollow body 15 and aterminal retaining portion 16. Rubber supply paths 17 and 17'penetrating through the hollow body 15 are provided at symmetrical rightand left positions about the center of the housing 14 and in thevicinity of the juncture of the hollow body 15 and the terminalretaining portion 16.

Tapered protrusions 18 and 18', which increase the outer diameter of theperipheral wall along a direction toward the juncture of the molds, areformed on the outer wall 15a of the hollow body 15 in the proximity ofeach open edge of the rubber supply paths 17 and 17'. The taperedprotrusions 18 and 18' are used as stocks for force fitting when afemale metal mold 19 (see FIG. 7) is mounted on the housing 14. Themaximum interval (S) between the tapered protrusions 18 and 18' isarranged to be greater than the inner diameter of a step 20a of thefemale metal mold 19, which will be described hereinafter. As is shownin FIG. 6, each of the tapered protrusions 18 and 18' has a square shapeso that they can easily be pressed down by the peripheral wall 20 of thefemale metal mold 19.

The female metal mold 19 is a mortar shaped mold to be mounted on themale metal mold 1. The step 20a, which is thinned along a directiontoward the opening, is provided at the edge portion of the opening ofthe peripheral wall 20. The step 20a is provided with rubber supplypaths 21 and 21' for forming the packing ring, both of which arecommunicated, respectively, with the rubber supply paths 17 and 17' ofthe housing 14. The inner diameter of the step 20a is so formed that ithas slightly larger diameter than the outer diameter of the hollow body15 of the housing 14.

To form a packing ring which is an integral part of the housing 14, thehollow body 15 of the housing 14 engages with the male metal mold 1 inthe same manner as in the aforesaid embodiment, and as is shown in FIG.8, the peripheral wall 6 of the male metal mold 1 and the peripheralwall 20 of the female metal mold 19 are fitted together. During thisprocess, as the female metal mold 1 a is forced to fit, the taperedprotrusions 18 and 18' of the housing 14 are forced to fit by the endportion of the peripheral wall 20 of the female metal mold 19, and theend potion of the wall 20 is engaged with the peripheral wall 6 of themale metal mold 1.

As a result, the housing 14 is held tightly against the stepped portion20a of the female metal mold 19 with the tapered protrusions 18 and 18',and the center of the female metal mold 19 and the center of the housing14 are aligned with each other. Accordingly, even if there is a slightdimensional error in the outer diameter of the hollow body 15 of thehousing 14, it is compensated for by the stocks for force fitting or thetapered protrusions 18 and 18', and the center of the female metal mold19 and the center of the housing 14 can be aligned with each other atall times.

After the female metal mold 19 has been mounted on the male metal mold1, a rubber material is introduced into the space 8 through the rubbersupply paths 21 and 21' of the female metal mold 19 and the rubbersupply paths 17 and 17' of the housing 14, and a packing ring can beformed as an integral part of the housing 14. Further, since the femalemold 19 and the housing 14 are held by aligning with their centers onthe same axis, a packing ring having a uniform thickness can be formed.

According to the present invention, since the engaging portion of themale metal mold is formed into a trapezoidal shape, and is held tightlyagainst the inner wall of the hollow body of the housing, even if thereis a slight dimensional error in the diameter of the inner wall of thehollow body of the housing, the center of the engaging portion and thatof the housing can easily be aligned with each other, and theproductivity for forming packing rings as integral parts of the housingwith uniform thicknesses is emphatically increased. Further, packingrings that have uniform thicknesses can be provided regardless of theaccuracy of the metal molds in use, and thereby reducing manufacturingcosts.

Further, according to the present invention, by mounting the housing,which carries tapered protrusions on its outer wall as stocks for forcefitting, on the male metal mold and the tapered protrusions are presseddown, for force fitting, by the peripheral wall of the female metal moldwhen both of the metal molds are engaged with each other. Therefore,even if there is a slight dimensional error in the size of the innerwall of the housing, the center of the female metal mold can be alignedwith the center of the housing. This in turn results in an increase ofthe productivity of the process in forming packing rings having uniformthicknesses.

Still further, according to the present invention, since the housing hasthe tapered protrusions in the proximity of the edges of the openings ofthe rubber supply paths of the outer wall of the housing, even if thereis a slight dimensional error in the size of the outer wall of thehousing, such error can be adjusted by the tapered protrusions when thehousing is fitted in the metal mold. Therefore, it is not necessarily berequired to increase the accuracy of metal molds in manufacturinghousings, and this results in a reduction of manufacturing costs.

Yet further, according to the present invention, as has been describedin relation to the effects of the manufacturing method, the productivityof the process to form packing rings having uniform thicknesses asintegral parts of the housings is considerably increased. Since thefemale metal mold is provided with a beveled surface where comes intocontact with the housing, the up-and-down movement of the housing isprevented from causing and the housing is held stably, this also resultsin an improvement of accuracy in forming packing rings.

Moreover, in accordance with the present invention, since the leaking ofrubber material can be prevented from causing when injecting the rubbermaterial, and this results in advantages in manufacturing rubber packingrings by eliminating defective products in the process.

It is to be understood by those skilled in the art that the foregoingdescription relates only to a preferred embodiments of the invention andthat various changes and modifications may be made in the inventionwithout departing from the spirit and scope thereof.

What is claimed is:
 1. A method of manufacturing a waterproof connectorhousing, wherein a hollow housing having walls containing opposed,substantially parallel internal surfaces is placed between a male moldand a female mold for forming a packing ring, and a rubber material isintroduced through passage means formed in said female mold into apacking ring-forming space that is defined by one or both of said maleand female molds so as to form a packing ring which is an integral partof said housing, comprising the steps of:providing said housing havingsubstantially parallel walls with wall-penetrating passages definingrubber material supply passages for communication with said packingring-forming space; providing said male mold with a cavity for receivingsaid housing walls, said cavity including a central engaging portionhaving tapered external surface means adapted to engage thesubstantially parallel internal surfaces of said walls remote from saidwall-penetrating passages and defining the ends of said housing walls;placing said housing on said male mold with said internal surfaces ofsaid housing walls in said cavity in engagement with said taperedexternal surface means of said male mold central engaging portion;moving said female mold axially with respect to said male mold tocompressively engage said housing and thereby tighten the engagementbetween said tapered external surface of said male mold central engagingportion and said internal surfaces of said housing walls while placingthe passage means in said female mold in registry with the wallpenetrating passages in said housing; and introducing said rubbermaterial through said passage means and forming a packing ring whileholding said male mold engaging portion in tight contact with said innersurfaces of the walls of said housing.
 2. A method of manufacturing awaterproof connector housing, wherein a hollow housing having wallscontaining opposed, substantially parallel internal surfaces is placedbetween a male mold and a female mold for forming a packing ring, and arubber material is introduced through passage means formed in saidfemale mold into a packing ring-forming space that is defined by one orboth of said male and female molds so as to form a packing ring which isan integral part of said housing, comprising the steps of:providing, onan outer surface of a wall of said housing, tapered protrusions whichincrease in dimension in a direction toward an open end of said femalemold; providing said housing with wall-penetrating passages extendingthrough said protrusions and defining rubber material supply passagesfor communication with said packing ring-forming space; providing saidmale mold with a cavity for receiving said housing walls and including aconcentric engaging portion having external surface means adapted toengage the substantially parallel internal surfaces of said walls remotefrom said wall-penetrating passages and defining the ends of saidhousing walls, placing said housing on said male mold with said internalsurfaces of said housing walls in said cavity in engagement with saidexternal surface means of said male mold concentric engaging portion;pressing said tapered protrusions on said housing by moving said femalemold axially with respect to said male mold in a direction of increasingdimension of said protrusions to tighten the engagement between saidfemale mold and said housing while placing the passage means in saidfemale mold in registry with the passages in said tapered protrusions;and introducing a rubber material through said supply passages into saidspace while holding said housing tightly in contact with said femalemold.